1. Field of the Invention
This invention relates to electrically driven apparatus for operating a railway point (or a railway switch as it is also known).
2. Description of the Prior Art
To switch a point by hand in an industrial yard using a heavy counter-weight to secure the position of the tongues of the point causes a high incidence of backache in the operating personnel. Especially in yards having points made of a very heavy rail profile, e.g. 64 kg per meter, this problem is acutely felt. A significant improvement in this respect is a hand-operated point switching arrangement having an over-center toggle spring mechanism to bias the tongues into their end positions. The closing force obtainable with the construction on the tongues of the point is however smaller than that obtainable by means of weights in the switching mechanism.
Known electrically driven apparatus for operating railway points switch the point and secure its position, but do not exert a positive closing force. In particular in heavy industrial application they have the disadvantage that maintaining the necessary adjustment tolerances requires much time and effort. U.S. Pat. No. 1,842,393 illustrates a known point-operating mechanism.
In industrial rail yards it often happens that -- in spite of regulations prohibiting it -- points are forced open by driving a vehicle through them from the trailing side. This can damage the locking mechanism and cause dislocation of the slide system with a risk of subsequent derailments. Moreover because of the number of adjustments of play necessary and because of wear, the costs of maintenance of railway points are rather high.